Donald J. Trump’s latest Twitter tirade takes aim at a most fascinating target: his fellow Republicans.

The president is now threatening reprisals against GOP members of Congress who fail to rise to his defense against growing questions about whether he broke the law while winning the presidency.

I guess I’m slow on the uptake. I am having difficulty imagining what in the world Trump hopes to accomplish by issuing these threats.

Some of his fellow Republicans are questioning the circumstances surrounding the president’s relationships with Russians who — according to U.S. intelligence experts — sought to meddle in our 2016 election.

“It’s very sad that Republicans, even some that were carried over the line on my back, do very little to protect their President,” Trump wrote on Twitter.

The president is going to need these folks. All of them, it seems. Yet he keeps pounding away at those upon he must depend.

Congressional Democrats are long gone. They aren’t going to stand up for a single Trump initiative, nor will they give him a break on the Russia investigation taking shape within the special counsel’s office and on congressional committees.

Trump also wrote: “As the phony Russian Witch Hunt continues, two groups are laughing at this excuse for a lost election taking hold, Democrats and Russians!”

This message has a ring of truth to it. Yes, Democrats are laughing as Trump and the Republicans keep tripping over themselves and each other while trying to fend off the criticism.

And what about the Russians? You’re damn right they’re laughing. They have accomplished their prime objectives, according to U.S. intelligence analysts: Their preferred candidate won the 2016 election and they also have managed to cast serious doubt on the integrity of the U.S. electoral system.